Engineering high coenzyme Q tomato.

Coenzyme Q (CoQ) is vital for energy metabolism in living organisms. In humans, CoQ deficiency causes diseases and must be replenished via diet; however, CoQ content in plant foods is primarily low. Here, we report the breeding of high CoQ tomato lines by expressing four enzymes with a fruit-specific promoter, which modifies the chloroplast chorismate pathway, enhances cytosolic isoprenoid biosynthesis, and up-regulates the first two reactions in mitochondrion that construct the CoQ polyisoprenoid tail. We show that, while the level of the aromatic precursor could be markedly elevated, head group prenylation is the key to increasing the final CoQ yield. In the HUCD lines expressing all four transgenes, the highest CoQ content (0.15 mg/g dry weight) shows a seven-fold increase from the wild-type level and reaches an extraordinarily rich CoQ food grade. Overviewing the changes in other terpenoids by transcriptome and metabolic analyses reveals variable contents of carotenoids and α-tocopherol in the HUCD lines. In addition to the enigmatic relations among different terpenoid pathways, high CoQ plants maintaining substantial levels of either vitamin can be selected. Our investigation paves the way for the development of CoQ-enriched crops as dietary supplements.